INDIANAPOLIS — As the flu season kicks off in the United States, halfway across the world, one of Australia’s worst flu seasons in recent years is winding down.

The Australian experience has led some flu pundits to predict we may have a similarly bad year here. But time could wind up disproving that notion, some experts say.

“Influenza can be more unpredictable than the weather,” said Dr. Christopher Belcher, medical director of infection control for St. Vincent Health. “So saying that Australia had a bad winter doesn’t necessarily mean we will see the same thing in the Northern Hemisphere.”

Hurricanes in Texas, Florida and the Caribbean and fires in the West may add a new dimension this year by interfering with medical routines for those who have been displaced, Kjersti Aagaard, a maternal-fetal medicine specialist at Texas Children’s Hospital in Houston, told USA TODAY.

And with people in shelters or bunking with family members, viruses can pass more easily, she said.

“We’re hitting the flu season kind of with a perfect storm,” Aagaard said.

Given that flu is a shifty actor, it’s hard to make any ironclad predictions about what, if anything, will set this flu season apart from others.

Still, here’s a quick primer with what you need to know:

Q: What does what happens in Australia have to do with our flu season?

A: Every year, scientists look towards the Southern Hemisphere to help hone their predictions for what might happen here. When choosing strains for the coming year’s flu vaccine, they consider what’s circulating in that part of the world.

Q: So is the strain that’s responsible for the flu in Australia in our flu vaccine?

A: That’s the good news. The culprit in Australia is the H3N2 strain of flu, which is included in this year’s vaccine and dates back to Hong Kong in 2014, said Dr. John Christenson, professor of clinical pediatrics at the Indiana University School of Medicine and chief of clinical services for the Ryan White Center for Pediatric Infectious Disease and Global Health at Riley Children's Hospital at IU Health.

And in a sign that perhaps those predictions are right, it’s also the most common strain circulating here right now, he added.

Q: If that strain is in the flu vaccine, why did so many people get sick?

A: H3N2 strains are the hardest ones for the flu vaccine to combat. All flu viruses make frequent genetic changes that help them slip around a vaccine. Influenza H3N2 viruses are particularly adept at changing as the vaccine is being made, rendering the vaccine less effective against them, according to the Centers for Disease Control and Prevention.

Scientists are working on ways to outsmart the virus. One way might be to find a production process that does not involve growing the virus in eggs, an environment that may promote the virus’s ability to change.

Q: Has our flu season started?

A: Influenza does not follow a strict calendar. Typically, however, in the United States, flu is most common between the months of October and May. Vaccine tends to become available in late summer or early fall.

Nationwide, all strains of the flu are circulating, said Shawn Richards, outbreak supervisor for the Indiana State Department of Health. Indiana has seen influenza A cases but so far there have been no confirmed cases of influenza B.

Belcher said that he has already had a patient hospitalized for influenza.

“It’s just that shot across the bow that it’s coming soon,” he said.

Q: Whatever happened to the nasal spray vaccine?

A: FluMist is gone for now, but not forgotten by those who abhore needles. After studies showed that the nasal spray option did not protect as well against the H1N1 flu strain, manufacturers pulled it off the market. They’re working on a more effective version and as soon as they have one available — perhaps as early as next year — it likely will be available once more, experts say.

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Researchers are testing a painless skin patch that features tiny, dissolvable needles full of the flu vaccine.
Video provided by Newsy
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Q: Should I not bother if I haven’t had my flu shot already?

A: The American Academy of Pediatrics this year recommended that all children be vaccinated by the end of October, if possible. But if Halloween comes and goes without a flu shot for you or your child, don’t panic. There’s still plenty of time, but try not to dally too much. Flu typically peaks around January and it takes a few weeks after getting the shot for your body to build its immunity.

If you already had your shot, there’s no need to worry about it wearing off, Belcher said. Studies have shown it still provides protection even if it’s given late in the summer.

Q: Does everyone really need the flu vaccine?

A: Vaccination is recommended for everyone over the age of six months. This year, doctors are even recommending it for people who are allergic to eggs, who previously were advised to avoid vaccination. Studies have shown that while the vaccine does contain egg protein, the amounts are so small that very few people with allergies react to the vaccine, Belcher said.

People with allergies are advised to consult their allergist.

Q: How many people are vaccinated each year?

A: Nationwide, about 43% of adults and 59% of children between the ages of six months and 17 years are vaccinated.

Q: But I’m healthy. Surely I don’t need a shot.

A: Even if you are healthy, you can still become ill. And if you do become ill and are around someone who is at higher risk — such as a baby too young for vaccination or a person with a compromised immune system — you could put them at risk.

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Wondering if you should get the flu vaccine if you already are moderately sick? Watch the video to learn what you should do.
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Q: Will one shot for life ever do the trick with the flu?

A: Rest assured scientists are working on it. But influenza is an ever-changing target and for now the only way scientists know to keep up is to produce a new vaccine each year.

“These viruses are very smart. They change the appearance of their surface proteins so they basically create new viruses,” Christenson said. “Germs are smart. They want to survive and that’s how they do it.”